The Amsler-Krumeich classification of keratoconus stages is based primarily on which clinical parameters?
- A Corneal topography indices (I-S ratio, KISA%) and biomechanics (CRF, CH)
- B Slit-lamp signs (Vogt's striae, Fleischer ring, Munson's sign) only
- C Refraction (myopia and astigmatism), mean keratometric reading, corneal thickness, and presence of corneal scarring ✓
- D Visual acuity and corneal optical coherence tomography pachymetric map
Correct answer: C. Refraction (myopia and astigmatism), mean keratometric reading, corneal thickness, and presence of corneal scarring
Explanation
The Amsler-Krumeich classification uses four stages based on: refraction (myopia/astigmatism degree), mean keratometric reading (flat and steep Ks), minimum corneal thickness, and presence of hydrops or scarring. Stage I has eccentric steepening and Ks <48D; Stage II has Ks 48–53D and thickness >400 µm; Stage III has Ks 53–55D and thickness 200–400 µm; Stage IV has Ks >55D, hydrops, or central scarring. This classification guides corneal crosslinking and transplantation decisions.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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